Decoding the New Diet Pills

Two new weight-loss drugs can help you shed pounds—if you meet certain conditions

by Norine Dworkin-McDaniel

Photograph: Shutterstock.com

In the last few weeks, struggling dieters have gotten a bit more ammunition for their battle against the bulge: For the first time in 13 years, the Food and Drug Administration approved a new weight-loss drug. Make that two new drugs: Belviq (locaserin) and Qsymia (a combination of the appetite suppressant phentermine and the anti-seizure/migraine drug topiramate). MORE got the skinny on both from Abraham Thomas, MD, MPH, head of endocrinology at Henry Ford Hospital in Detroit and chair of the FDA advisory panels that evaluated the medications.

Can anyone use these drugs for weight loss?
These aren’t for people who just want to drop a few pounds. They’re intended for those who are obese (BMI 30+) or overweight (BMI 27+) with at least one weight-related condition, like hypertension, high cholesterol, diabetes or sleep apnea. Your doctor will be able to prescribe both Belvig and Qsmyia, but to avoid misuse, Qsmyia will only be dispensed by mail order pharmacies who register to carry it. (Qsmyia.com will post a pharmacy list when the drug becomes available.)

How do these drugs work?
Both medications curb appetite and help you feel full on fewer calories. Belviq works by acting somewhat like the neurotransmitter serotonin. The phentermine part of Qsymia controls appetite mainly by increasing your amounts of the neurotransmitter norepinephrine and to a lesser degree, dopamine and serotonin. Topiramate is believed to work by boosting feelings of fullness.

Is one drug more effective than the other?
The drugs haven’t been tested against each other, but separate studies suggest that more people lose more weight with Qsymia. Some 62 to 70 percent of those on this combo medication lost at least 5 percent of their starting weight (for a 170-pound woman that’s 8.5 or more pounds), and 15 percent lost considerably more: 20 percent (at 170 pounds, that comes to 34 pounds). The latter number is in the range of what you can lose with gastric bypass surgery. In contrast, 47 percent of those taking Belviq lost 5 percent of their weight.

It should be noted that to get these kinds of results, you also need to diet and exercise while taking the medications.

Is one safer?
Qsymia is associated with more risks (including elevated heart rate and blood pressure, cognitive dysfunction, and birth defects) than Belviq (depression, migraines, memory problems), one reason the combo drug will be so carefully controlled. Given the risks of obesity itself, the FDA panel thought that the benefits of the two medications outweighed their risks.

Do the drugs work for everyone?
If one of these drugs is going to work for you, you should be losing at least a half-pound to a pound a week during the first 12 weeks of taking it. If not, talk to your doctor about upping your dose if you’re on Qsymia or changing drugs. Since the drugs work in different ways, switching from one to the other may be helpful.